No Life 'Til Leather is Metallica's widely circulated demo tape featuring Dave Mustaine and Lloyd Grant on guitars and Ron McGovney on bass. All the tracks are early recordings of songs that would later appear on the band's Kill 'Em All album. The track listing on Kill 'Em All is the same as that on the demo tape, save the addition of Cliff Burton's bass solo "(Anesthesia) Pulling Teeth", "Whiplash", "No Remorse" and "The Mechanix" (the latter of which was re-written by Metallica as "The Four Horsemen").

The demo has been re-released twice so far unofficially, first under the title of Metallica—Bay Area Trashers, and was alleged to be a live bootleg recording of Metallica in the early days, however all 'live' sounds had been added from various sources including the Metallica video Cliff 'Em All. Soon this was discovered by Metallica and all copies were removed from stores. The second time it was re-released was under the title Metallica—In the Beginning... Live, which is exactly the same as Metallica—Bay Area Trashers, but simply with a new title.

This is the most well-known Metallica demo, showing the band's NWOBHM roots very clearly. The tracks are quite similar to the final versions on Kill 'Em All, apart from the modified lyrics for "The Mechanix" and "Jump In The Fire". "The Mechanix", a Mustaine written composition, turned into Metallica's own "The Four Horsemen". Mustaine recorded his own version of "The Mechanix" on Megadeth's debut album Killing Is My Business... And Business Is Good! The album, along with two other songs, can be found floating on many peer-to-peer networks under the moniker "One Last Visit".